A method of reacting (meth)acrylic acid with an alkylene oxide is known as a method for producing a hydroxyalkyl (meth)acrylate. In this method, it is generally carried out to use an excess number of moles of alkyl ester as compared with a number of moles of (meth)acrylic acid.
Therefore, when (meth)acrylic acid is reacted with an alkylene oxide and thus a reaction liquid containing a hydroxyalkyl (meth)acrylate is obtained, an unreacted alkylene oxide is contained in the reaction liquid.
As a method for recovering the alkylene oxide in the reaction liquid, a method of reducing a pressure in a reactor to vaporize the alkylene oxide into gas in the reactor and then introducing the gas into an absorption tower to absorb the alkylene oxide in the gas into (meth)acrylic acid in the absorption tower is proposed (for example, Patent Document 1).